Method of producing optoelectronic semiconductor components and an optoelectronic semiconductor component

ABSTRACT

An optoelectronic semiconductor component includes a primary light source including a carrier and a semiconductor layer sequence mounted thereon and configured to generate primary light, and at least one conversion unit of at least one semiconductor material adapted to convert the primary light into at least one secondary light, wherein the semiconductor layer sequence and the converter unit are separate elements, the semiconductor layer sequence includes a plurality of pixels, the pixels are configured to be controlled electrically independently of each other, the carrier includes a plurality of control units configured to drive the pixels, all pixels of a first group are free of a conversion unit and are configured to emit the primary light, all pixels of a second group of pixels include exactly one conversion unit each and are configured to emit the at least one secondary light.

TECHNICAL FIELD

This disclosure relates to a method of producing optoelectronicsemiconductor component and an optoelectronic semiconductor component.

BACKGROUND

There is a need to provide an optoelectronic semiconductor componentwith many pixels, that is adjustable to emit light in different colors,and can be produced efficiently.

SUMMARY

We provide a method of producing optoelectronic semiconductor componentsincluding providing a primary light source having a carrier and asemiconductor layer sequence mounted thereon that generates primarylight (B), wherein the semiconductor layer sequence is structured into aplurality of pixels that can be driven electrically independently ofeach other, and the carrier includes a plurality of control units thatdrive the pixels, providing at least one conversion unit adapted toconvert the primary light (B) into at least one secondary light (G,R),wherein the conversion unit is grown continuously from at least onesemiconductor material, structuring the conversion unit, whereinportions of the semiconductor material are removed in accordance withthe pixels, and applying the conversion unit to the semiconductor layersequence so that the remaining semiconductor material is uniquelyassigned to a portion of the pixels.

We also provide an optoelectronic semiconductor component including aprimary light source including a carrier and a semiconductor layersequence mounted thereon that generate primary light (B), and at leastone conversion unit of at least one semiconductor material adapted toconvert the primary light (B) into at least one secondary light (G,R),wherein the semiconductor layer sequence and the conversion unit areproduced separately from each other and are not grown together, thesemiconductor layer sequence is structured into a plurality of pixelsthat can be controlled electrically independently of each other, thecarrier includes a plurality of control units that drives the pixels, noconversion unit is assigned to some of the pixels so that selectedpixels emit the primary light (B), and exactly one conversion unit eachis assigned to remaining pixels, a plurality of pixels emittingdifferent colors are combined to form a display area that is adjustableto emit light of different colors, and a light path between the carrierand a light-exit side of the conversion unit facing away from thecarrier is free of organic materials.

We further provide an optoelectronic semiconductor component including aprimary light source including a carrier and a semiconductor layersequence mounted thereon and configured to generate primary light, andat least one conversion unit of at least one semiconductor materialadapted to convert the primary light into at least one secondary light,wherein the semiconductor layer sequence and the converter unit areseparate elements, the semiconductor layer sequence includes a pluralityof pixels, the pixels are configured to be controlled electricallyindependently of each other, the carrier includes a plurality of controlunits configured to drive the pixels, all pixels of a first group arefree of a conversion unit, and the pixels of the first group areconfigured to emit the primary light, all pixels of a second group ofpixels include exactly one conversion unit each, and the pixels of thesecond group are configured to emit the at least one secondary light, aplurality of pixels from the first group and the second group arecombined to form a display area that is adjustable to emit light ofdifferent colors, and a light path between the carrier and a light-exitside of the conversion unit facing away from the carrier is free oforganic materials.

We further yet provide an optoelectronic component including a primarylight source including a carrier and a semiconductor layer sequencemounted thereon that generate primary light, and at least one conversionunit of at least one semiconductor material adapted to convert theprimary light into at least one secondary light, wherein thesemiconductor layer sequence and the conversion unit are producedseparately from each other and are not grown together, the semiconductorlayer sequence is structured into a plurality of pixels that can becontrolled electrically independently of each other, the carrierincludes a plurality of control units that drive the pixels, noconversion unit is assigned to some of the pixels so that selectedpixels emit the primary light, and exactly one conversion unit each isassigned to remaining pixels, a plurality of pixels emitting differentcolors are combined to form a display area that is adjustable to emitlight of different colors, and a light path between the carrier and alight-exit side of the conversion unit facing away from the carrier isfree of organic materials.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1F, 2A-2B, 3A-3C, and 6A-6B are schematic sectionalrepresentations of process steps of examples of methods described forthe production of optoelectronic semiconductor components.

FIGS. 4, 5 and 7 are schematic sectional views of examples ofoptoelectronic semiconductor components.

REFERENCE CHARACTER LIST

-   1 optoelectronic semiconductor component-   2 primary light source-   21 carrier-   22 semiconductor layer sequence-   22 a first semiconductor layer sequence-   22 b second semiconductor layer sequence-   23 control unit-   24 pixels-   25 opaque partition wall-   26 separation region-   27 raw material layer-   3 first conversion unit-   31 semiconductor material-   4 second conversion unit-   40 light-exit side-   41 semiconductor material-   5 growth substrate-   6 display area (pixels)-   71 mirror layer-   72 filter layer-   73 planarization layer-   B primary light-   B1 first primary light-   G first secondary light-   G2 second primary light-   R second secondary light-   R1 secondary light

DETAILED DESCRIPTION

Our method produces optoelectronic semiconductor components. Several ofthe semiconductor components can be produced together in a wafercomposite. The optoelectronic semiconductor components are adapted togenerate color-adjustable light. The produced semiconductor componentsserve, for example, as display devices, as displays or in spotlightswith adjustable emission characteristics, for example, in motorvehicles.

The method may comprise the step of providing a primary light source.The primary light source generates electromagnetic radiation, especiallyprimary light, via electroluminescence. Primary light is preferably bluelight, for example, with a wavelength of maximum intensity of at least420 nm or 435 nm and/or at most 480 nm or 460 nm.

The primary light source may alternatively or additionally generateelectromagnetic radiation in other wavelength ranges. For example, theprimary light source may produce ultraviolet radiation alternatively orin addition to blue light, for example, with a wavelength of maximumintensity at 365 nm minimum and/or 420 nm maximum. For example, theprimary light source may produce green light alternatively or inaddition to blue light, for example, with a wavelength of maximumintensity at 485 nm minimum and/or 575 nm maximum.

The primary light source may comprise a carrier. The carrier contains alarge number of control units. In particular, the carrier is asilicon-based semiconductor carrier comprising transistors and/orswitching units and/or control units. The control units can be producedin CMOS technology. The carrier is preferably based on a semiconductormaterial such as silicon or germanium.

A semiconductor layer sequence may be attached to the carrier. Thesemiconductor layer sequence is adapted to generate the primaryradiation. For this purpose, the semiconductor layer sequence comprisesat least one active zone. The semiconductor layer sequence is preferablybased on a III-V compound semiconductor material. For example, thesemiconductor material is a nitride compound semiconductor material suchas AlnIn1-n-mGamN or a phosphide compound semiconductor material such asAlnIn1-n-mGamP or also an arsenide compound semiconductor material suchas AlnIn1-n-mGamAs or such as AlnIn1-n-mGamAskP1-k, wherein: 0≤n≤1,0≤m≤1 and n+m≤1 and 0≤k<1. Preferably, 0<n≤0.8, 0.4≤m<1 and n+m≤0.95 and0<k≤0.5 applies to at least one layer or to all layers of thesemiconductor layer sequence. The semiconductor layer sequence maycontain dopants and additional components. For the sake of simplicity,however, only the essential components of the crystal lattice of thesemiconductor layer sequence are indicated, i.e., Al, As, Ga, In, N orP, even if they may be partially replaced and/or supplemented by smallquantities of other substances.

In the method, the semiconductor layer sequence may be structured into aplurality of electrically independently controllable pixels in planview. This structuring is carried out in particular by removing materialfrom part of the semiconductor layer sequence. In other words, thesemiconductor layer sequence is structured by etching. Preferably,material is removed from the semiconductor layer sequence betweenadjacent pixels.

The pixels may be electrically contacted independently of each other andcan be controlled independently of each other. The independent controlis effected via the control units in the carrier. Preferably, one of thecontrol units of the carrier is assigned to each of the pixels and viceversa.

The method may include the step of providing one or more conversionunits. At least one conversion unit is adapted to partially orcompletely absorb the primary light and convert it into at least onesecondary light. The secondary light is generated by photoluminescencefrom the primary light.

The conversion unit or all conversion units may be grown contiguouslyfrom at least one semiconductor material. In particular, each conversionunit is epitaxially grown. The conversion units can be based on the samesemiconductor materials as the semiconductor layer sequence of theprimary light source, or on different semiconductor materials.

The conversion units that generate the secondary light may each comprisea single quantum well structure or, preferably, a multiple quantum wellstructure. This means that the conversion units can be composed of asequence of several semiconductor layers. In a lateral direction, inparticular parallel to a main expansion direction of the carrier, acomposition of the conversion units prefers not to change or not tochange significantly. In other words, the semiconductor layers of theconversion units continue over the entire respective conversion unit,preferably in an unchanged composition within the manufacturingtolerances.

The conversion units may be structured. During structuring, thesemiconductor material from which the conversion units are made isremoved in subareas. It is preferred to completely remove thesemiconductor material in the sub-areas so that, seen from above,recesses and/or holes are created in the conversion units. Furthermore,it is possible that only islands of the semiconductor material of theconversion units remain, which are not interconnected by semiconductormaterial of the respective conversion unit.

Structuring of the at least one conversion unit may take place accordingto the pixels of the semiconductor layer sequence. For example, the samegrid is used to structure the semiconductor material used to structurethe semiconductor layer sequence into the pixels. Thus, it is possibleto assign at least a part of the pixels to each area of thesemiconductor material of the conversion unit so that the correspondingpixel generates the secondary light during operation.

The structured conversion unit may be applied to the semiconductor layersequence. This results in an assignment of the remaining semiconductormaterial of the conversion layers after structuring to a part of thepixels. This assignment is preferably unambiguous.

The method may be established to produce optoelectronic semiconductorcomponents and may comprise the following steps, for example, in thegiven order:

-   -   providing a primary light source having a carrier and a        semiconductor layer sequence attached to generate primary light,        wherein the semiconductor layer sequence in plan view is        structured into a plurality of electrically independently        controllable pixels, and the carrier comprises a plurality of        driving units that control the pixels,    -   providing at least one conversion unit adapted to convert the        primary light into at least one secondary light, wherein the        conversion unit is grown continuously from at least one        semiconductor material,    -   structuring the conversion unit, wherein partial regions of the        semiconductor material are removed according to the pixels, and    -   applying the conversion unit to the semiconductor layer sequence        so that the remaining semiconductor material is uniquely        assigned to a part of the pixels.

The primary light source may be constructed as specified in DE 10 2014101 896 A1 or DE 10 2014 105 999 A1, the subject matter of which withregard to the primary light source is incorporated herein by reference.Such primary light sources comprising a carrier with control units and asemiconductor layer sequence structured in pixels are also referred toas microlight emitting diodes, or micro LEDs for short.

Micro LEDs are mostly monochromatic emitting components. To produce acolored image with three monochromatic micro LEDs, one for red light,one for green light and one for blue light, the emitted light by themicro LEDs can be mixed and superimposed via a prism. It is alsopossible to generate a color image directly from the emission ofindividual pixels, wherein individual different colors emitting pixelsof a semiconductor material can either be placed side by side or stackedvertically on top of each other. However, such arrangements are eithervery time-consuming to produce due to the fact that individual pixelshave to be placed individually, or have additional optical components.

With our method, on the other hand, a semiconductor component in theform of a micro LED can be efficiently produced, wherein the individualpixels result from a single semiconductor layer sequence. By applying atleast one conversion unit, compact and efficiently producible pixels canbe generated that emit light in different colors. This is achieved inparticular by structuring the conversion units according to the divisionof the semiconductor layer sequence into pixels. Both the conversionunits and the semiconductor layer sequence can be produced at waferlevel.

By generating different colors by photoluminescence in the conversionunits, it is possible to use a monochromatically emitting primary lightsource in the form of a micro LED. For example, the arrangement ofelectrical contacts and passivation layers is comparatively simple andefficient compared to other methods. The use of epitaxially grownsemiconductor layers for the conversion units enables generation of alayer stack containing several layers emitting in different wavelengths.Furthermore, with such semiconductor layers for the conversion units itis possible to achieve a high degree of absorption, especially for bluelight so that a local full conversion of the primary light can beachieved. In addition, spectrally narrow-band spectra of the respectivephotoluminescence radiation can be obtained. This opens up a wide gamutrange in display applications, for example. Since at a certain locationabove the semiconductor layer sequence only one single conversion unitis particularly preferred, undesired absorption losses can be avoided.The use of planarization processes to fill gaps between semiconductormaterial areas of the conversion units enables mechanical stabilization.In addition, the conversion units can be directly bonded to the primarylight source.

When structuring the semiconductor layer sequence to the pixels, thereneed not be a change in the position of remaining regions of thesemiconductor layer sequence relative to each other. In other words, theareas for the individual pixels are not first juxtaposed by a subsequentplacement process, but the pixels are created directly from thesemiconductor layer sequence without subsequent rearrangement orrepositioning. This also applies to the structuring of the conversionunits. This means that even the remaining parts of the semiconductormaterial of the conversion units are not changed with regard to theirposition and position relative to each other after or duringstructuring.

Several conversion units may be applied to the semiconductor layersequence. Exactly two conversion units are preferred. A first conversionunit converts blue light into green light, and a second conversion unitconverts blue light into red light. If the primary light source emitsultraviolet radiation and little or no blue light, a third conversionunit is preferred to generate blue light.

The semiconductor layers of the conversion units may be grown on top ofeach other on a common growth substrate. In other words, the conversionunits can form a common, coherently grown semiconductor layer sequence.

One or more of the conversion units may be structured on the commongrowth substrate. The structuring is, for example, photolithographicallydone and by etching. It is preferable to structure the conversion unitsone after the other in time.

In the method, only one of the conversion units need be structured onthe common growth substrate. After structuring this conversion unit, thecompound of the conversion units and the common growth substrate may beattached to the semiconductor layer sequence, preferably by waferbonding. The growth substrate is then removed, for example, by lasertreatment, etching and/or mechanical methods such as grinding. Finally,at least one further conversion unit is structured, wherein thisstructuring takes place at the semiconductor layer sequence of theprimary light source.

Several conversion units may be applied to the semiconductor layersequence of the primary light source. Each of the conversion units isgrown on its own growth substrate. The conversion units thus eachrepresent a separately produced, separate semiconductor layer sequence.

The conversion units may be structured on the respective growthsubstrate. This makes it possible to avoid structuring the conversionunits directly on the semiconductor layer sequence.

One or more planarization layers may be applied after structuring thecorresponding conversion unit. The planarization layer is made of aradiation-permeable material and preferably consists of inorganicmaterials, for example, an oxide such as silicon oxide or aluminiumoxide or a nitride such as silicon nitride or aluminium nitride.

The planarization layer may mechanically connect individual island-likeareas of the conversion units resulting from the structuring of thesemiconductor material. A material for the planarization layer can belocated directly on the semiconductor material of the conversion units.Alternatively, it is possible that a coating, especially an opticallyfunctionalized coating such as an optical insulation or a mirror islocated between the material of the planarization layer and thesemiconductor material of the conversion units.

The planarization layer may partially or completely cover a side of theconversion unit facing away from the associated growth substrate. Theplanarization layer can cover this side permanently or only temporarilyduring certain producing steps.

The conversion units may each be grown on separate growth substrates.Subsequently, the conversion units may be attached to each other beforethe growth substrates are detached, in particular by direct bonding withor without an intermediate layer. This creates a layer sequence from theconversion units.

The sequence of layers from the conversion units may be structured,where in particular, only one of the conversion units is structured.Subsequently, this layer sequence is attached to the semiconductor layersequence of the primary light source. The remaining growth substrate canbe removed then. The previously unstructured conversion unit can then bestructured.

The conversion units may be attached to each other or the conversionunits may be attached to the semiconductor layer sequence by waferbonding. This can be wafer bonding without an intermediate layer, inparticular so-called direct bonding or anodic bonding. Alternatively, aparticularly oxidic or nitridic intermediate layer can be used and waferbonding is eutectic bonding, glass bonding or adhesive bonding.

A light path between the carrier and a light exit side of the conversionunits facing away from the carrier may be free of organic material. Inother words, light may only pass through inorganic materials within thesemiconductor component. This results in a long service life and highpower densities, especially of blue light, can be achieved.

Some of the pixels may not be assigned to any of the conversion units.The primary light is emitted from these pixels without wavelengthconversion. Furthermore, exactly one of the conversion units may beassigned to each of the other pixels. This means that there are noconversion units stacked on top of each other at the pixels. Forexample, pixels that emit the primary light without wavelengthconversion are present that emit blue light. In addition, pixels may bepresent that emit the primary light without wavelength conversionemitting green light. For example, it is possible that blue and greenlight are generated by an electrically pumped stack of layers and redlight is generated by an optically pumped semiconductor layer.

Several, in particular exactly three, differently colored emittingpixels may be combined to one display area. Such display areas are alsoreferred to as colored pixels. The display areas can emit light indifferent colors. By arranging the pixels in display areas, it ispossible to use the semiconductor component to display images or filmsor varying light patterns.

Adjacent pixels and/or adjacent display areas may be optically isolatedfrom each other by a partition wall. The partition wall can be composedof one or more opaque materials. The partition may be absorbent orreflective to the radiation produced.

The partition wall may extend completely through the conversion unit. Itis possible for the partition wall to be flush with the semiconductorlayer sequence or partially or completely penetrate the semiconductorlayer sequence. If the intermediate wall protrudes into thesemiconductor layer sequence, the intermediate wall is, for example,made of an electrically insulating material or electrically insulatingtowards the semiconductor layer sequence. Alternatively, it is possiblethat, for example, an n-conducting side of the semiconductor layersequence is electrically contacted via the partition walls so that acommon electrical contact across the pixels can be realized through thepartition wall.

The semiconductor layer sequence may be continuous and contiguous andpreferably extends seamlessly across all pixels. Alternatively, thesemiconductor layer sequence may be completely removed in areas betweenadjacent pixels and/or display areas so that the pixels or display areasare realized by islands out of the semiconductor layer sequence.

At least one mirror layer may be applied to one side of the conversionunits facing the semiconductor layer sequence. The one or more mirrorlayers are impermeable or largely impermeable to the secondary lightgenerated in the associated conversion unit. The mirror layers arepreferably used to reflect this secondary light. In particular, themirror layers are transparent to the primary light and realized bydichroic mirrors.

There may be at least one filter layer on one side of the conversionunits facing away from the carrier. The filter layer is impermeable toprimary light and permeable to secondary light. The filter layer canabsorb or reflect the primary light. Optionally, the filter layer can bedesigned as an anti-reflective layer for the secondary light.

The filter layer and/or mirror layer may completely cover the associatedconversion unit. Alternatively, the associated conversion unit is onlypartially covered by the filter layer and/or mirror layer.

At least one of the conversion units or all conversion units and/or thesemiconductor layer sequence may have a thickness of at least 1 μm or 2μm and/or a thickness of at most 15 μm or 10 μm or 6 μm. In other words,the conversion units and the semiconductor layer sequence are thin.

The pixels may have an average diameter of at least 2 μm or 3 μm or 10μm in plan view. Alternatively or additionally, the mean diameter is atmost 300 μm or 200 μm or 80 μm. In particular, these values apply notonly to the mean diameter, but also to a mean edge length of the pixelsif they are square or rectangular in shape in plan view.

A distance between adjacent pixels may be at least 0.3 μm or 0.5 μm or 1μm and/or at most 10 μm or 6 μm or 3 μm. The distance between the pixelsshall preferably not exceed 25% or 10% or 3% of the mean diameter of thepixels.

The finished semiconductor device may comprise at least 10 or 100 or1000 of the pixels. Alternatively or additionally, the number of pixelsshall not exceed 108 or 107 or 106 or 105. The same may apply to thenumber of display areas.

We also provide an optoelectronic semiconductor device. Thesemiconductor device is preferably produced by methods as indicated inconjunction with one or more of the above examples. Features for themethods are therefore also disclosed for the semiconductor device andvice versa.

The optoelectronic semiconductor device may comprise a primary lightsource comprising a carrier and a semiconductor layer sequence attachedto generate primary light. The semiconductor device further comprises atleast one conversion unit of at least one semiconductor material, theconversion unit being adapted to convert the primary light into at leastone secondary light by photoluminescence. The semiconductor layersequence and the conversion unit are produced separately from each otherand are not grown together. Seen from above, the semiconductor layersequence is structured into a large number of electrically independentlycontrollable pixels. The carrier comprises a large number of controlunits that control the pixels and are preferably available in a 1:1assignment to the pixels. Some of the pixels are not assigned aconversion unit so that these pixels emit the primary light and theremaining pixels are each assigned exactly one conversion unit.

Several pixels emitting different colors are combined to form a displayarea designed to emit light that can be adjusted in terms of color.Furthermore, a light path between the carrier and a light exit side ofthe conversion unit facing away from the carrier is free of organicmaterials.

In the following, a process described here and a semiconductor componentdescribed here are explained in more detail with reference to thedrawing using examples. The same reference signs indicate the sameelements in the individual figures. However, no true-to-scale relationsare shown. Rather, individual elements may be exaggeratedly large for abetter understanding.

FIGS. 1A-1F schematically illustrate a method of producingoptoelectronic semiconductor components 1. According to FIG. 1A, agrowth substrate 5 is provided. Growth substrate 5, for example, is aGaAs substrate. Two semiconductor materials 31, 41 are grown on growthsubstrate 5 for two conversion units 3, 4. First, a second semiconductormaterial 41 is grown to generate red light and then a firstsemiconductor material 31 to generate green light.

The two semiconductor materials 31, 41 are based on InGaAlP. The secondsemiconductor material 41 that generates red light is preferably basedon InGaAlP. As an alternative to InGaAlP, the first semiconductormaterial 31 can also be based on InGaN, grown, for example, on asapphire substrate. Such a translucent sapphire substrate can alsoremain attached to the semiconductor material 31, in contrast to FIGS.1A-1F. The semiconductor materials 31, 41 each consist of several layersand preferably comprise a multiquantum well structure adapted togenerate green or red secondary light by photoluminescence.

For example, a multiquantum well structure may comprise ten or morequantum well structures. For example, the multiquantum well structure inthe first semiconductor material 31 may comprise twenty or more quantumwell structures. Furthermore, the multiquantum well structure in thefirst semiconductor material 31 may comprise, for example, one hundredor fewer quantum well structures. For example, the multiquantum wellstructure in the second semiconductor material 41 may comprise twenty ormore quantum well structures. Furthermore, the multiquantum wellstructure in the second semiconductor material 41 may, for example,comprise one hundred or fewer quantum well structures. According to oneexample, the number of quantum well structures in the first and/orsecond semiconductor material is between twenty and fifty quantum wellstructures. The number of quantum well structures in the firstsemiconductor material 31 and the number of quantum well structures inthe second semiconductor material 41 may be different. Further, thenumber of quantum well structures in the first and/or secondsemiconductor material 31, 41 may be greater than the number of quantumwell structures in the semiconductor layer sequence 22 of the primarylight source 2.

The process step of FIG. 1B shows that the first semiconductor material31 is structured. The first semiconductor material 31 is completelyremoved in areas, in particular by etching so that the secondsemiconductor material 41 is exposed in areas. Otherwise, the secondsemiconductor material 41 remains unaffected by this structuring.

The structuring of the first semiconductor material 31 is carried out,for example, by wet chemical or dry chemical etching. The individual,remaining island-shaped regions of the first semiconductor material 31correspond to the size of pixels 24 of the semiconductor component 1.The island-shaped regions have, for example, an edge length of at least3 μm and/or at most 200 μm. Seen from above, these areas are square,rectangular, round or hexagonal. These areas can be cartesian in arectangular pattern or hexagonal. The same applies to the secondsemiconductor material 41 and also to all other examples.

In the process step of FIG. 1C1, a planarization layer 73 is depositedover the entire surface. The planarization layer 73 is preferably madeof an electrically insulating dielectric material such as silicondioxide. The planarization layer 73 fills gaps between the island-like,remaining regions of the first semiconductor material 31 so that a totallayer with a constant thickness is formed. In addition, theplanarization layer 73 firmly connects the island-shaped regions of thefirst semiconductor material 31 with each other. The planarization layer73 forms together with the first semiconductor material 31 the firstconversion unit 3.

According to FIG. 1C1, the planarization layer 73 has the same thicknessas the first semiconductor material 31 so that the first semiconductormaterial 31 and the planarization layer 73 are flush with each other,directing away from the growth substrate 5. In contrast, FIG. 1C2illustrates that a thickness of the planarization layer 73 is greaterthan a thickness of the first semiconductor material 31. On a sidefacing away from the growth substrate 5, the first semiconductormaterial 31 is completely covered by the planarization layer 73. Theplanarization layer 73 together with the first semiconductor material 31again has a constant thickness. This thickness is at least 5 μm and/orat most 12 μm, for example, with the planarization layer 73 preferablyexceeding the first semiconductor material 31 by at most 5 μm or 2 μm or1 μm. This also applies preferentially to all other examples.

The variants with regard to the planarization layer 73, as illustratedin FIGS. 1C1 and 1C2, can also be found in all other examples. Tosimplify the illustration, only one of these variants is illustratedbelow.

FIG. 1D shows that the composite of FIG. 1C1, or alternatively FIG. 1C2,is attached to a primary light source 2. This is preferably done bydirect bonding. The composite of FIG. 1C1 can directly connect to asemiconductor layer sequence 22 of the primary light source 2 as shownin FIG. 1D. Alternatively, it is possible to apply an unrepresentedintermediate layer such as silicon dioxide, between the primary lightsource 2 and the composite of FIG. 1C1 to mediate adhesion.Alternatively, the planarization layer 73 from FIG. 1C2 can be used asan adhesion promoter.

The primary light source 2 also has a carrier 21. The carrier 21contains a large number of control units 23. The carrier 21 ispreferably based on silicon, and the control units 23 are produced inCMOS technology in the carrier 21. The semiconductor layer sequence 22is based on AlInGaN and is designed to generate blue light. Thesemiconductor layer sequence 22 is divided into a number of pixels 24.Each of the pixels 24 is preferably assigned to exactly one of thecontrol units 23 and vice versa.

Separation areas 26 are optionally located between adjacent pixels 24.Electrical and/or optical isolation of the individual pixels 24 fromeach other can be achieved via the separation areas 26. Thesemiconductor layer sequence 22 is only partially interrupted by theseparation areas 26, for example, in form of unfilled or filledtrenches, and extends as a continuous layer over the entire carrier 21.Seen from above, the pixels 24 are, for example, rectangular, square,round or hexagonal.

At the process step of FIG. 1E, the growth substrate 5 from FIG. 1D isremoved. The growth substrate 5 is removed by grinding, polishing, wetor dry etching, laser lifting or combinations thereof.

Subsequently, in FIG. 1F, the second semiconductor material 41 isstructured in the same way as the first semiconductor material 31,wherein the structuring is performed on the semiconductor layer sequence22. The semiconductor layer sequence 22 is not affected by thisstructuring. A further planarization layer 73 is also applied. Thefurther planarization layer 73 forms together with the secondsemiconductor material 41 the second conversion unit 4.

The island-shaped remaining areas of the two semiconductor materials 31,41 have the same size as the areas of the semiconductor layer sequence22 for the pixels 24. For example, a third of the pixels 24 is free ofthe conversion units 3, 4 in an RGB unit or a quarter of the pixels 24is free of the conversion units 3, 4 in—an RGGB unit so that a primarylight B, preferably blue light, is emitted directly from these pixels24. Only one of the conversion units 3, 4 is assigned to each of theremaining pixels 24. First, secondary light G and second secondary lightR are generated via the conversion units 3, 4, wherein green and redlight are preferred. In the conversion units 3, 4, the primary light Bis completely or almost completely absorbed.

Three pixels 24, emitting different colors, are combined to form adisplay area 6, also known as a pixel. The pixels are adapted to emitlight of different colors, which is composed of the primary light B andthe secondary light G, R.

In FIGS. 1A-1F, the individual display areas 6 each have exactly onearea for red, green and blue light, thus forming an RGB unit. There canalso be two areas for green light so that an RGGB unit with four pixels26 is formed, or an additional unit for yellow light for an RGBY unit.It is also possible to add a fluorescent unit to produce white light,resulting in an RGBW unit. White or yellow light is generated in a notshown third conversion unit stacked above the first and secondconversion units 3, 4. The display areas 6 preferably comprise eachexactly three or four of the pixels 26. An ultraviolet-emittingsemiconductor layer sequence can also be present as primary source 2provided with three phosphors for red, blue and green and optionally foryellow or white, wherein the individual phosphor areas can be preferablyexcited independently of each other.

Since the conversion units 3, 4 do not overlap at the semiconductorlayer sequence 22, the conversion units 3, 4 can be applied in anyorder.

In addition to the planarization layers 73 of FIG. 1F, others notillustrated, especially transparent thin layers can also be used asadditional or alternative passivation and/or encapsulation. In additionto silicon dioxide, the planarization layers 73, the optionalintermediate layer and the passivation and/or encapsulation can also bemade of silicon nitride, aluminum oxide, tantalum nitride, transparentoxides or nitrides of Zn, Sn, Ta, Ga, Ni, Zr, Hf, Ti or rare earthmetals. The two planarization layers 73 can be made of the same materialor of different materials.

To avoid a complex adjustment between the pixels 24 of the semiconductorlayer sequence 22 and the structured conversion units 3, 4, emission ofprimary radiation from the semiconductor layer sequence 22 can be usedby certain actively operated pixels 24 to locally cure or solubilizephotoresists. This is, for example, done when structuring the conversionunits 3, 4 directly on the semiconductor layer sequence 22 as shown inFIG. 1F.

For improved light extraction, the conversion units 3, 4 or thesemiconductor layer sequence 22 can each have a roughening on a sidefacing away from the carrier 21. It may be possible to apply additionalprotective layers to such a roughening, which can be planarizedoptionally. Furthermore, the planarization layers 73 or at least oneplanarization layer 73 remote from the carrier 21 can be roughenedoptionally.

In the process of FIGS. 2A and 2B, particularly FIG. 2A, thesemiconductor materials 31, 41 are grown on two different growthsubstrates 5. Subsequently, as shown in FIG. 2B, the semiconductormaterials 31, 41 are bonded together and one of the growth substrates 5is removed.

In the process illustrated in FIGS. 3A-3C, semiconductor materials 31,41 are grown on separate growth substrates 5 and also structured ongrowth substrates 5 as shown in FIG. 3A. The planarization layers 73 areapplied subsequent as shown in FIG. 3B.

Subsequently, either the two conversion units 3, 4 are first connectedand then attached to the semiconductor layer sequence 22, or theconversion units 3, 4 are attached sequentially to the semiconductorlayer sequence 22, as shown in FIG. 3C.

In the example of semiconductor component 1 as shown in FIG. 4 , thereare opaque partition walls 25 a, 25 b between adjacent pixels 24.Optical isolation between pixels 24, or alternatively only betweenadjacent display areas 6, can be achieved via these partition walls 25a, 25 b and optical crosstalk is reduced or prevented. Thus, moresaturated colors can be displayed and a larger gamut range can beachieved.

The partition walls 25 a, 25 b can be created by structuring theconversion units 3, 4, for example, by metallic or dielectric mirroringof etched flanks of the semiconductor materials 31, 32 before generatingthe corresponding planarization layer 73. The partition walls 25 a, 25 bcan also be created after generating the planarization layer 73, forexample, by etching trenches and subsequent filling with reflective orabsorbing material.

Partition walls 25 a can be limited to conversion units 3, 4. Thepartitions 25 a do only reach the semiconductor layer sequence 22, butdo not reach into the semiconductor layer sequence 22. On the otherhand, in partition walls 25 b generated subsequently after structuringthe conversion units 3, 4, they can reach into the semiconductor layersequence 22 and completely penetrate the semiconductor layer sequence22, optionally together with the optionally available separating regions26.

The partition walls 25 a, 25 b, for example, are made of a metal. If thepartitions 25 b are made of an electrically conductive material, thepartitions 25 b especially prefer not to reach a non-drawn metallizationbetween the pixels 24 to avoid electrical short circuits. Alternatively,an electrical contacting of the semiconductor layer sequence 22 can beachieved via the partition walls 25 a, 25 b on a side facing away fromthe carrier 21. The partition walls 25 a, 25 b can also be metal spacersor optical separations generated by photo technology.

It is possible that individual pixels are structured on 24 p sides, forexample, in particular on a side facing the carrier 21. For ann-contact, especially on a side facing away from the carrier 21, thesemiconductor layer sequence 22 between adjacent pixels 24 can bepartially removed. For better optical isolation of the pixels 24 fromeach other, the n-conducting GaN can be removed from the n side to thisn contact then, especially before the conversion units 3, 4 are applied.All conversion units 3, 4 can also be applied first, structured andplanarized, and a trench or recesses between the individual pixels 24 isonly subsequent structured, especially lithographically. These trenchesor recesses filled with a reflective or absorbent material can extendinto the n-GaN.

Such partition walls 25 a, 25 b can also be present in all otherexamples. In the semiconductor component 1, only the partition walls 25a of the left half of the picture in FIG. 4 or only the partition walls25 b of the right half of the picture are preferred.

In the example of FIG. 5 , additional mirror layers 71 and/or filterlayers 72 are provided. The mirror layers 71, for example, dichroicand/or dielectric mirrors are each located on a side of the associatedconversion unit 3, 4 facing the primary light source 2. In particular,the mirror layers 71 are directly attached to the semiconductor material31, 41. The mirror layers 71 ensure that the secondary light generatedfrom the primary light does not return to the semiconductor layersequence 22. In contrast to FIG. 5 , it is possible that the mirrorlayer 71 is generated continuously directly at the semiconductor layersequence 22 and not at the first or second semiconductor material 31,41.

Alternatively or in addition to the mirror layers 71, filter layers 72are available. The filter layers 72 prevent unconverted, in particularblue primary light from exiting the individual pixels 24. The filterlayer 72 can be applied continuously over several of the pixels 24 or belimited to individual pixels 24.

FIGS. 6A and 6B illustrate a method of producing the partition walls 25a. According to FIG. 6A, a raw material layer 27 is applied to thestructured semiconductor material 31 continuously and conformally with aconstant thickness. For example, the raw material layer 27 is a metallayer. The raw material layer 27 is applied, for example, by chemicalvapor deposition, physical vapor deposition, atomic layer deposition orsputtering.

Subsequently as shown in FIG. 6B, an anisotropic etching such as dryetching takes place so that the raw material layer 27 remains only onthe flanks of the semiconductor material 31 and thus forms the partitionwalls 25 a.

The process steps of FIGS. 6A and 6B can, for example, be additionallyperformed in the process steps of FIG. 1B or 3A or 1F.

In context to FIG. 7 , a further example is described in which pixels 24are present that emit a first primary light B1 without a wavelengthconversion. In addition, pixels 24 are present that emit a secondprimary light G2 without wavelength conversion. The first primary lightB1 is blue light, the second primary light G2 is green light. Blue andgreen light are generated by electric pumping. There are also pixels 24that emit secondary light R1, for example, red light. The red light isgenerated by the second conversion units 4.

The semiconductor layer sequence 22 has a first semiconductor layersequence 22 a that generates the second primary light G2 and a secondsemiconductor layer sequence 22 b that generates the first primary lightB1. The layer sequence directed away from the carrier 21 in thesemiconductor layer sequence 22 is, for example, as follows: firstsemiconductor layer sequence 22 a comprising a p-doped layer, forexample, p-GaN, an active layer that generates green light, an n-dopedlayer, for example, n-GaN, tunnel contact, second semiconductor layersequence 22 b comprising a p-doped layer, for example, p-GaN, an activelayer that generates blue light, an n-doped layer, for example, n-GaN.

For blue pixels 24, the p-doped layer and the active layer that generategreen light of the first semiconductor layer sequence 22 a are removed.The n contact connects to the upper n-doped layer of the secondsemiconductor layer sequence 22 b.

For green pixels 24, the n contact connects to the lower n-doped layerof the first semiconductor layer sequence 22 a. The not shown n contactis led out laterally.

For red pixels 24, the p-doped layer and the active layer that generategreen light of the first semiconductor layer sequence 22 a can beremoved. The n contact connects to the upper n-doped layer of the secondsemiconductor layer sequence 22 b. Alternatively, the p-doped layer andthe active layer can remain to generate green light and can be used toexcite a conversion unit 4. In this example, the n contact connects tothe lower n-doped layer of the first semiconductor layer sequence 22 a.

Our methods and components are not limited by the description given inthe examples. Rather, this disclosure includes each new feature as wellas each combination of features including in particular the combinationof features in the appended claims, even if the feature or combinationitself is not explicitly specified in the claims or examples.

Priority of DE 102016220915.9 is claimed, the subject matter of which isincorporated herein by reference.

The invention claimed is:
 1. An optoelectronic semiconductor componentcomprising: a primary light source comprising a carrier and asemiconductor layer sequence mounted thereon and configured to generateprimary light, and at least one conversion unit of at least onesemiconductor material adapted to convert the primary light into atleast one secondary light, wherein the semiconductor layer sequence andthe converter unit are separate elements, the semiconductor layersequence comprises a plurality of pixels, the pixels are configured tobe controlled electrically independently of each other, the carriercomprises a plurality of control units configured to drive the pixels,all pixels of a first group are free of a conversion unit, and thepixels of the first group are configured to emit the primary light, allpixels of a second group of pixels comprise exactly one conversion uniteach, and the pixels of the second group are configured to emit the atleast one secondary light, a plurality of pixels from the first groupand the second group are combined to form a display area that isadjustable to emit light of different colors, and a light path betweenthe carrier and a light-exit side of the conversion unit facing awayfrom the carrier is free of organic materials.
 2. The optoelectronicsemiconductor component according to claim 1, wherein the semiconductorlayer sequence and the conversion unit are produced separately from eachother and are not grown together.
 3. The optoelectronic semiconductorcomponent according to claim 1, wherein the semiconductor layer sequenceand the conversion unit are in direct physical contact with each other.4. The optoelectronic semiconductor component according to claim 1,wherein the semiconductor layer sequence is structured into theplurality of pixels that can be controlled electrically independently ofeach other.
 5. The optoelectronic semiconductor component according toclaim 1, wherein no conversion unit is assigned to the pixels of thefirst group so that selected pixels emit the primary light.
 6. Theoptoelectronic semiconductor component according to claim 1, wherein thesecond group of pixels comprises a first sub-group of pixels configuredto emit green light.
 7. The optoelectronic semiconductor componentaccording to claim 1, wherein the second group of pixels comprises asecond sub-group of pixels configured to emit red light.
 8. Theoptoelectronic semiconductor component according to claim 1, wherein thesemiconductor layer sequence is based on AlInGaN, the semiconductormaterial is based on AlInGaN, AlInGaP or AlInGaAs, and the carrier isbased on Si or Ge.
 9. The optoelectronic semiconductor componentaccording to claim 1, wherein adjacent pixels are optically isolated byan opaque partition wall from each other, the partition wall completelypenetrating at least one conversion unit and at least partially thesemiconductor layer sequence.
 10. The optoelectronic semiconductorcomponent according to claim 1, wherein the semiconductor layer sequenceextends continuously and contiguously over all the pixels.
 11. Theoptoelectronic semiconductor component according to claim 1, wherein atleast one mirror layer is applied to a side of the conversion unitsfacing the semiconductor layer sequence, and the mirror layer isimpermeable to the secondary light produced in an associated conversionunit and permeable to the primary light.
 12. The optoelectronicsemiconductor component according to claim 1, wherein at least onefilter layer is applied to a side of the conversion units facing awayfrom the carrier, the filter layer is impermeable to the primary light,and the filter layer completely covers the conversion units.
 13. Theoptoelectronic semiconductor component according to claim 1, wherein theconversion unit or each of the conversion units and/or the semiconductorlayer sequence have a thickness of 1 μm to 10 μm, the pixels having anaverage diameter of 3 μm to 200 μm in plan view, a distance betweenadjacent pixels is 0.3 μm to 6 μm, and the semiconductor componentincludes 100 to 10⁷ of the pixels.
 14. An optoelectronic semiconductorcomponent comprising: a primary light source comprising a carrier and asemiconductor layer sequence mounted thereon that generate primarylight, and at least one conversion unit of at least one semiconductormaterial adapted to convert the primary light into at least onesecondary light, wherein the semiconductor layer sequence and theconversion unit are produced separately from each other and are notgrown together, the semiconductor layer sequence is structured into aplurality of pixels that can be controlled electrically independently ofeach other, the carrier comprises a plurality of control units thatdrive the pixels, no conversion unit is assigned to some of the pixelsso that selected pixels emit the primary light, and exactly oneconversion unit each is assigned to remaining pixels, a plurality ofpixels emitting different colors are combined to form a display areathat is adjustable to emit light of different colors, and a light pathbetween the carrier and a light-exit side of the conversion unit facingaway from the carrier is free of organic materials.